Folding step stool



FIG. 1 is a perspective view of a folding step stool illustrating our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof in an opened position, with the left side elevational view being substantially similar;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a right side elevational view thereof in a closed position. 

The ornamental design for a folding step stool, as shown and described. 